Contributions to the Chemistry of Chlorophyll. 309 



eras residue. Chromic acid acts in a similar manner. Treated with 

 boiling concentrated nitric acid, phylloxanthin is decomposed, a 

 quantity of yellow semi-fused fatty matter being left behind ; the 

 filtrate leaves on evaporation a crystalline residue, consisting mainly 

 of oxalic acid. 



A chloroformic solution of phylloxanthin when exposed to sunlight 

 in a loosely stoppered bottle gradually becomes paler, and at last 

 almost colourless. No difference in the rapidity of bleaching could 

 be observed when a solution of phyllocyanin of as nearly as possible 

 the same strength was exposed to the action of light along with the 

 solution of phylloxanthin. The process is doubtless one of slow oxi- 

 dation under the influence of light. 



On adding a little bromine to a chloroformic solution of phyllo- 

 xanthin the colour of the latter changes to a bright grass-green, 

 resembling that of chlorophyll solutions, but its spectrum differs 

 from that of chlorophyll, as well as from that of phylloxanthin ; it 

 shows one very broad band, extending over a great part of the red 

 and the whole of the orange, with a faint band in the green, and an 

 indication of one nearer the blue, together with much obscuration at 

 the blue end. The solution leaves on evaporation a little amorphous 

 residue, which is purple by reflected, and dark green by transmitted, 

 light, and contains bromine. On adding an excess of bromine to a 

 chloroformic solution of phylloxanthin the colour of the solution 

 changes to a deep yellow, but it still shows a band in the red. 



On treating phylloxanthin with concentrated hydrochloric acid in 

 the cold no change takes place at first, but after some time a great 

 part of the substance dissolves, yielding a dark greenish-blue solu- 

 tion, while part remains undissolved as a green fatty mass, which 

 may be separated by filtration through asbestos. The filtrate appears 

 slightly more green than a solution of phyllocyanin in hydrochloric 

 acid, but it shows nearly the same spectrum as the latter, though the 

 bands of which it consists are far less distinct and well marked. The 

 solution, when shaken up with ether, imparts no colour to the latter, 

 behaving in this respect like a solution of phyllocyanin, which shows 

 that phylloxanthin by treatment with hydrochloric acid undergoes 

 some change. Nevertheless, when the product of the action is pre- 

 cipitated from the acid solution by water the precipitate, after filter- 

 ing off and washing, dissolves in ether, yielding a solution which 

 shows the colour and absorption spectrum of a solution of phyllo- 

 xanthin. The precipitated product dissolves also in glacial acetic 

 acid boiling, and the solution on cooling deposits a portion which, 

 when filtered off and dried, appears dark blue, like phyllocyanin, and 

 when viewed under the microscope shows the same indistinctly 

 crystalline form as the latter. In all other respects, however, it gives 

 the same reactions as phylloxanthin, so that it is certain no trans- 



